Technical Field
The present disclosure relates to a solenoid device that includes two electromagnetic coils and two plungers, and a solenoid system in which the solenoid device is used.
Related Art
As a component that is used in a relay and the like, a solenoid device is known that moves a plunger in a forward and backward direction, using an electromagnetic coil (refer to JP-A-2014-170738). The solenoid device includes two electromagnetic coils and two plungers. A stationary core composed of a soft magnetic material is disposed within each electromagnetic coil. Each plunger is disposed such as to oppose the stationary core with a predetermined distance therebetween. When the electromagnetic coil is energized, magnetic force is generated. The plunger is attracted to the stationary core. The solenoid device is configured to move the plungers in the forward and backward direction by energizing and deenergizing the electromagnetic coils.
As described hereafter, in the above-described solenoid device, there is a case in which both of the two plungers are attracted to the stationary cores, and a case in which only either of the plungers is attracted to the stationary core. The amount of time over which both of the two plungers are attracted to the stationary cores is long. In this case, there is a need for power consumption of the electromagnetic coils to be reduced. To address this need, the solenoid device is configured in the following manner.
That is, the electromagnetic coils are a first electromagnetic coil and a second electromagnetic coil. The plungers are a first plunger and a second plunger.
In the case in which only either (first plunger) of the plungers is attracted, both of the two electromagnetic coils are energized (see FIG. 15). Magnetic flux generated by energization of the first electromagnetic coil flows through a first magnetic circuit and a third magnetic circuit (shared magnetic circuit). The first magnetic circuit includes only the first plunger of the two plungers. The third magnetic circuit includes both of the two plungers. A magnetism limiting portion that limits magnetic flux is formed in the first magnetic circuit. As a result, the magnetism limiting portion limits the magnetic flux of the first magnetic circuit. Excess magnetic flux flows through the third magnetic circuit.
In addition, the magnetic flux generated by energization of the second electromagnetic coil flows through the third magnetic circuit in a direction opposite that of the magnetic flux flowing through the first electromagnetic coil. As a result, the magnetic flux of the first electromagnetic coil flowing through the third magnetic circuit is canceled by the magnetic flux of the second electromagnetic coil. Therefore, the magnetic flux apparently does not flow through the third magnetic coil, but flows through only the first magnetic coil. Only the first plunger is attracted.
In the case in which both of the two plungers are attracted, the two electromagnetic coils are energized. Then, energization of the second electromagnetic coil is stopped (see FIG. 16). As a result, the magnetic flux of the second electromagnetic coil dissipates, and the magnetic flux of the first electromagnetic coil continues to flow through the third magnetic circuit. Therefore, both of the two plungers can be attracted. At this time, because the second electromagnetic coil is not energized, the two plungers can be continuously attracted, while suppressing power consumption.
However, in the above-described solenoid device, a problem occurs in that it is difficult to stably attract only the first plunger. That is, in the solenoid device, in the case in which only the first plunger is attracted, the two electromagnetic coils are energized. The magnetic flux of the first electromagnetic coil flowing through the third magnetic circuit is cancelled by the magnetic flux of the second electromagnetic coil. Therefore, the amount of magnetic flux of the first electromagnetic coil and the amount of magnetic flux of the second electromagnetic coil flowing through the third magnetic coil are required to be substantially equal. The amount of magnetic flux generated by an electromagnetic coil may vary depending on temperature and the like. Therefore, the amount of generated magnetic flux is difficult to adjust.
In addition, a situation in which a malfunction occurs in either of the electromagnetic coils and sufficient magnetic flux is not generated is also possible. Consequently, a likelihood can be considered in that, in the above-described solenoid device, even should attraction of only the first plunger be attempted, the magnetic fluxes of the two electromagnetic coils are not completely canceled out in the third magnetic circuit. The remaining magnetic flux flows through the third magnetic circuit, and both of the two plungers are attracted